1. Field of the Invention
The invention relates in general to a self-powered hub that can supply power actively, and more particularly to a hub that can supply power to connected equipment actively without depending on the universal serial bus (USB) of a computer to supply power.
2. Description of the Related Art
The universal serial bus (USB) for computers was developed by large manufacturers such as INTEL™. The USB can simultaneously connect a computer to peripheral equipment of up to 127 devices. A basic interface specification of the USB includes a positive/negative data line D+, D− and a positive/negative power cord V+ and V−, which is the most common and popular USB interface. Despite the USB being able to connect up to 127 peripheral devices simultaneously, USB ports in a computer are actually limited. If desiring to extend usages of the peripheral equipment of the USB interface, a hub is the best choice. The hub is used to extend the quantity of the USB connection ports, so as to extend the peripheral equipment of the USB interface of the computer. As described above, since the USB is provided with the power cord, the computer can supply power to the peripheral equipment via the USB. However, there is a premise for this function.
Firstly, since the computer supplies power via the USB, no matter whether the peripheral equipment is connected to the computer directly or via the hub, the power only can be supplied in an online state. Hence the power cannot be supplied in an off-line state.
Secondly, since the USB can connect to 127 peripheral devices at the same time, even though it is not possible to connect to so many peripheral devices in practice, it is likely to connect to several USB interface peripheral devices and all of the devices consume power simultaneously. In such a circumstance, the direct current supplied by the USB is insufficient.
To sum up, although the computer can use the hub to extend the quantity of the connected USB interface peripheral devices, once the hub is offline or connects to several peripheral devices consuming power simultaneously, the power supply of the USB is definitely insufficient. Thus, there is a need for the hub to overcome the aforementioned drawbacks.